Piperonal, also known as heliotropin, has a sweet cherry and vanilla aroma. The piperonal is widely applied in food flavor, cosmetic, pharmaceutical, agricultural and electroplating industries. Natural heliotropinis mainly found in plants such as melon, Robinia pseudoacacia, allspice, and vanilla beans, but the content is extremely small, and people cannot directly extract the natural heliotropin from plants.
At present, the heliotropin is industrially produced mainly by a semi-synthesis method using safrole as a raw material and a total synthesis method using catechol as a raw material. The method seriously pollutes the environment and consumes much energy. With the increasing attention of people on the material production process and the increasing requirements for food additives, flavor substances synthesized by a bio-fermentation method and enzymatic method are increasingly favored by people.
Microbial synthesis of piperonal is currently not applied to industrial production. The Santos team in Brazil found several strains of microbes of producing piperonal with isosafrole. The most efficient strain is Paecilomyces variot bainier, but only under the condition that H2O2 is added, the highest yield is 64 mg/L, and the transformation rate is only 20%. In Chinese patent CN105779363A, it is found that a strain of Serratia liquefaciens produces 282 mg/L of piperonal.
Therefore, how to improve enzyme activity of trans-anethole oxygenase and accelerate catalytic synthesis rate of piperonal is a technical problem to be solved urgently in the field of microbial synthesis of piperonal.